TABLE 2.

Estimation of the fraction of genomes in nine metagenomes containing genes specific to Cyanobacteria, Chlorobi, and Desulfobacteraceae, based on the frequencies of protein-coding genes unique to aerobic or anaerobic carbon fixation and SSU rRNA gene copy number per average genome^a

Sample	Proportion (fraction) of genomes carrying traitb			SSU rRNA gene copy no.
	Calvin-Benson cycle	Total rTCA	Chlorobi-type rTCA
GS017	0.15	—	—	1.29
GS026	0.20	—	—	1.10
GS027	0.06	—	—	1.39
Site 227	0.04	0.12	0.04	1.38
Site 228	0.03	0.17	0.06	1.20
Site 229	0.02	0.26	0.14	1.14
Site 230	0.004	0.69	0.65	0.93
Site 231	0.46	0.07	—	2.40
Site 232	0.21	0.06	0.04	2.17

^aValues based on data from Table S6 in the supplemental material. rTCA stands for reductive tricarboxylic acid cycle.

^b—, not detected.